[Colloquium] Reminder: Talk by Stefano Allesina, NCEAS Today
Katie Casey
caseyk at cs.uchicago.edu
Thu Apr 17 07:46:30 CDT 2008
DEPARTMENT OF COMPUTER SCIENCE
UNIVERSITY OF CHICAGO
Date: Thursday, April 17, 2008
Time: 2:30 p.m.
Place: KPTC 120
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Speaker: Stefano Allesina
From: NCEAS
Web page: http://www.nceas.ucsb.edu/~allesina/
Title: Stability in Ecological Networks: Large Effects of Small Motifs
Abstract: Large number of species interact and coexist in the
intricate networks of consumer–resource interactions known as food
webs. For decades ecologists held the view that more complex
ecosystems, those with a larger number of species and connections,
were also more likely to be persistent, explaining therefore the
extremely high biodiversity we observe in nature. Robert May's
mathematical argument on stability, however, proved that large,
complex networks of ecological interactions with random structure tend
invariably to instability. This result ignited the "complexity-
stability" debate that has been one of the main drivers of theoretical
ecology for three decades. Here we revisit May's argument and show
that, when species interact as predators and prey, systems as complex
as the ones observed in nature can still be stable. Moreover,
stability is highly robust to perturbations of interaction strength,
and is largely a property of structure driven by predator–prey loops.
The results highlight the role of small modules for the persistence of
large networks, so that the stability of small motifs can cascade in
that of the whole network.
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